This clinical course will present the current understanding of the MS prodrome. The MS prodrome will be contrasted with other neurological conditions. The diagnosis of the radiologically isolated syndrome and clinical management will be highlighted. Using data from population-based studies, risk factors for MS in the prodromal stage will be highlighted along with imaging and fluid biomarkers. Modifiable risk factors and potential MS prevention strategies will be discussed. A case discussion will provide the form for clinical applications of these concepts to be reviewed. Level of Information: IntermediateThis clinical course will present the current understanding of the MS prodrome. The MS prodrome will be contrasted with other neurological conditions. The diagnosis of the radiologically isolated syndrome and clinical management will be highlighted. Using data from population-based studies, risk factors for MS in the prodromal stage will be highlighted along with imaging and fluid biomarkers. Modifiable risk factors and potential MS prevention strategies will be discussed. A case discussion will provide the form for clinical applications of these concepts to be reviewed. Level of Information: Intermediate